How do you make a good bass cover?

[JUSTINKP]

I used the search, and really didn't find anything that relates to me and my equipment. Was wondering if I could get some help.

I really want to make some bass covers for youtube.

My setup in my computer room includes:

Fender Rumble 75 combo bass amp
iMac Computer
Cables, 1/4 to 1/8 adapter, etc. Everything needed to record.

The issues I'm running into are:

I have photobooth on my mac which will take video with my webcam and record the sound through the microphone on the mac or through the line in port.

My first attempt, I used the internal mic. This turned out bad. You could barely hear my bass amp, but what was the worst, was the song playing during my cover was all distorted and sounded like crap.

So for attempt number 2, I used the line out port of my Fender Amp and got a 1/4 to 1/8 adapter and plugged it into the line in on my mac. I put volume low on my amp, and adjusted the mac volume to get a good volume of my bass in the computer. I recorded the video and my bass into the computer, and it sounded great. My issue is syncing the video with the mp3 of the song I have. I know how to mix the sound to make my bass line a little louder than the mp3, but I can't sync the video to get it in time with Imovie or Final Cut Pro softwares. They are not user friendly at all.

Does anyone have suggestions for good software, free or low in cost to use to sync my videos? Better yet, does someone know a better software to be recording my cover with?

Thanks in advance for any and all help.